Due to the height of the body or frame of most cargo carrying delivery type trucks, steps must be provided on the truck frame which are located below the truck body to enable a workman to enter and leave the cargo area in a convenient and safe manner. Certain of these trucks are provided with a rigid frame that is attached to the truck body that extends downwardly therefrom to provide steps for the workman, such as shown in U.S. Pat. Nos. 2,660,454 and 3,858,905. These frames or steps also function as bumpers for the truck when it strikes an object or is struck by another vehicle.
One problem that occurs frequently with such delivery trucks is that the bumper and step portion is often damaged when the truck is backed into a loading dock due to the poor visibility of the dock to the driver or inattention by the driver during the backing procedure. Even though these truck steps and bumper combinations are made of rigid metal, they are subject to bending and breaking when the vehicle backs into a loading dock. This requires the entire unit to be removed from the truck frame and straightened and welded to the vehicle frame or the damaged parts replaced and welded onto the existing frame. All such repairs require time and expense.
There are several prior devices which have been devised in an attempt to overcome the damage problem by providing some type of shock absorbing mechanism whereby the bumper and/or step will pivot or move upon striking an object. Examples of such devices are shown in U.S. Pat. Nos. 2,544,799, 3,210,110, 3,913,963, 3,923,330 and 4,247,138. Although these devices do provide a solution to the problem, they are relatively expensive and require a number of specially designed and constructed parts and only provide a pivotally mounted bumper without providing a series of steps which is desirable to facilitate the loading and unloading of the truck by workmen.
The bumper constructions of U.S. Pat. Nos. 3,913,963 and 4,247,138 are believed to be the closest prior art to the present invention. The bumpers of these patents require a mounting arrangement in which the bumper is mounted on an arm which projects outwardly from the vehicle whereby the bumper is spaced forwardly or rearwardly from the front or rear of the vehicle. The bumper of U.S. Pat. No. 3,913,963 is pivotally mounted on its mounting arm in order for the bumper to displace in a direction having a horizontal component. Such pivotal mounting of the bumper would make it completely unsatisfactory as a step. The bumper of U.S. Pat. No. 4,247,138 uses a bellcrank configuration and a lost motion arrangement for mounting of the bumper bar which also does not function as a step.
There is no known combination truck bumper and step device of which I am aware which provides both the features of the shock absorbing bumper for mounting on the truck in combination with a plurality of rigidly mounted steps for the safety and convenience of a workman when entering and leaving the cargo area.